A turbocharged engine mounted on a vehicle requires a technology for detecting abnormalities of a turbine and compressor which are rotating bodies.
One example of an abnormality detector for detecting an abnormality of a measured portion of a conventional rotating body is a crank angle sensor diagnosis device described in PTL 1. PTL1 describes a method of detecting a damage of a tooth of a rotating body by a decrease in the number of pulses between reference signals from a normal number of pulses.
PTL 2 describes a method in which when an abnormality is detected at an interval of a part of a plurality of pulses, it is determined that an abnormality of the tooth of the rotating body occurs.
PTL 3 describes a frequency divider circuit that outputs one pulse each time the frequency divider circuit counts a predetermined number of measurement signals.